Landing Flap Video

Check out...

http://www.youtube.com/watch?v=PXwy7dsLndM

....for a nice/useful/short video of two flapped landings in an HP-14,
owned/flown/filmed by Wayne Paul (and posted here with his permission).
Curious reader-pilots may find the following information helpful, should they
attempt to extract directly-/potentially-useful-to-them-information from the
video:
- "The tow pilot confirms my estimate that the winds were less than five knots."
- The distance from the beginning of asphalt to the start of the first stripe
is 120 feet.
- The stripe length is 120 feet.
- The stripe spacing is 80 feet. (Hence the distance from the start of one
stripe to the start of the next is 200 feet.)
- I have no idea where the roundout-aiming-point was for either landing.

For curious readers perhaps not terribly familiar with the traits/benefits of
large-deflection landing flaps, this video nicely illustrates some 'you can
bank on it' aspects of 'em.

1) When I estimate both landings' touchdown points and further estimate the
landing rolls, I come up with ~300 feet in both cases. The reason the landing
roll doesn't decrease from the 60-degree-flapped touchdown to the
90-degree-flapped touchdown, is because (for all practical purposes) flaps
stop adding lift after about 30-45 degrees of deflection; beyond that they add
only drag. But the short rollout distance nicely illustrates the
speed-reducing benefits of flaps.

2) Though it's impossible to tell from the video at what point the
60-/90-degrees of flap are deployed, one *can* get a sense for the drag
increment of those last 30-degrees by contrasting the approach angles on short
final, prior to roundout initiation. Steep approach without speed
increase...very nice; also very stable, wonderful visibility, simple to judge
one's roundout point, and great fun!

HP-14's land at ~5.5psf wing loading. It's an accurate statement that - when
Joe Pilot is using full flaps - they can easily/safely be put into fields
unavailable to 1-26 drivers, simply because they can approach more steeply
over field-bordering obstacles. As for the rollout, how many 1-26 drivers
routinely roll no more than 300 feet on a hard surface after touchdown? (And
how long does your skid plate last?)

IMHO, large deflection landing flaps on gliders are the best kept sailplane
secret in the last half century.

Enjoy!
Bob W.

On 8-2-2011 02:15, BobW wrote:


IMHO, large deflection landing flaps on gliders are the best kept
sailplane secret in the last half century.

Enjoy!
Bob W.

As a noob to gliders (coming from powered airplanes), I always thought
that spoilers were "the bomb" One thing I like about spoilers over
flaps is that you can go from full spoilers to no spoilers instantly
without bad effects. Can't do that with flaps...if you misjudge and put
on too much, too early, there isn't much you can do except
undershoot...but maybe you can dump some flaps since gliders tend to
have more wing to work with than their powered brothers. But it does
make sense that you can probably land shorter with these type of flaps
over just spoilers. Now I'll have to go watch the video

Lots have been said about flaps-reducing while on final.
I know at least of one other ASH25 pilot who has done it
gently without harmful effects (on final).
Last week, I've tried it in calm evening air at 1500 feet,
checking 2 independent digital altimeters.
A gentle reduction from from 'L' position to neutral made us
loose about 10 feet (natural ~5 second descent included).
A brutal 'L' to 'N' caused a 25-30 feet loss.
Some sailplanes are probably less forgiving.
I'd be glad to hear about pilots who have tried it for real.
wv


On Tue, 02 Aug 2011 10:35:37 +0000, Scott
wrote:

On 8-2-2011 02:15, BobW wrote:


IMHO, large deflection landing flaps on gliders are the best kept
sailplane secret in the last half century.

Enjoy!
Bob W.

As a noob to gliders (coming from powered airplanes), I always thought
that spoilers were "the bomb" One thing I like about spoilers over
flaps is that you can go from full spoilers to no spoilers instantly
without bad effects. Can't do that with flaps...if you misjudge and put
on too much, too early, there isn't much you can do except
undershoot...but maybe you can dump some flaps since gliders tend to
have more wing to work with than their powered brothers. But it does
make sense that you can probably land shorter with these type of flaps
over just spoilers. Now I'll have to go watch the video

In article , BobW
wrote:

Check out...

http://www.youtube.com/watch?v=PXwy7dsLndM

...for a nice/useful/short video of two flapped landings in an HP-14,
owned/flown/filmed by Wayne Paul (and posted here with his permission).
Curious reader-pilots may find the following information helpful, should they


Nice. Enjoyed the videos.


Had the distinct privilege of flying an HP-16 once (Thanks Dr. Jim). It
has the infamous "flaps and V-tail of death" that I had always heard
spell certain doom. In spite of the hype from know-it-alls who had never
actually flown with flaps or V-tails, I found the handling of the V-tail
was indistinguishable from that of a cruciform or T tail glider and the
flaps were just tremendous fun. In the pattern, I turned final at 600
feet and when the numbers disappeared under the nose I started rolling
in flaps. I kept on rolling in flaps until the numbers appeared again.
The horizon was way up the canopy at this point. Glanced at the airspeed
and it read 60 mph, so I rolled in a little more flap. I don't think I
ever actually reached the full 90 degree deflection. When the ground got
close enough that I could not stand it, I counted to three (quickly) and
flared. Touched down just past my aim point, slightly tail low, and
made a very short rollout. Not much different from landing an older
Cessna with big flaps and power off.

I think flaps for glidepath control on gliders got a bad rap because
some models of the Schweizer 1-35 had inadequate flap and were flown by
those who were not careful to control their speed on final.

Dr Jim's HP-16 is beautiful!!
http://www.soaridaho.com/Schreder/HP...rst_Flight.htm

Wayne
HP-14 "6F"

"Berry" wrote in message
...

In article , BobW
wrote:

Check out...

http://www.youtube.com/watch?v=PXwy7dsLndM

...for a nice/useful/short video of two flapped landings in an HP-14,
owned/flown/filmed by Wayne Paul (and posted here with his permission).
Curious reader-pilots may find the following information helpful, should
they


Nice. Enjoyed the videos.


Had the distinct privilege of flying an HP-16 once (Thanks Dr. Jim). It
has the infamous "flaps and V-tail of death" that I had always heard
spell certain doom. In spite of the hype from know-it-alls who had never
actually flown with flaps or V-tails, I found the handling of the V-tail
was indistinguishable from that of a cruciform or T tail glider and the
flaps were just tremendous fun. In the pattern, I turned final at 600
feet and when the numbers disappeared under the nose I started rolling
in flaps. I kept on rolling in flaps until the numbers appeared again.
The horizon was way up the canopy at this point. Glanced at the airspeed
and it read 60 mph, so I rolled in a little more flap. I don't think I
ever actually reached the full 90 degree deflection. When the ground got
close enough that I could not stand it, I counted to three (quickly) and
flared. Touched down just past my aim point, slightly tail low, and
made a very short rollout. Not much different from landing an older
Cessna with big flaps and power off.

I think flaps for glidepath control on gliders got a bad rap because
some models of the Schweizer 1-35 had inadequate flap and were flown by
those who were not careful to control their speed on final.

On 8/2/2011 4:35 AM, Scott wrote:
On 8-2-2011 02:15, BobW wrote:


IMHO, large deflection landing flaps on gliders are the best kept
sailplane secret in the last half century.

Enjoy!
Bob W.

As a noob to gliders (coming from powered airplanes), I always thought that
spoilers were "the bomb" One thing I like about spoilers over flaps is that
you can go from full spoilers to no spoilers instantly without bad effects.

A comforting - if not terribly accurate (see next para.) - theoretical thought
indeed. However, in the real world, there are precious few times when Joe
Clued-in Glider Pilot would actually want to or *need* to go from full
spoilers/flaps to none... assuming any halfway-decent landing pattern that
didn't also involve some sort of arcane practice.

Can't do that with flaps...if you misjudge and put on too much, too early,
there isn't much you can do except undershoot...but maybe you can dump some
flaps since gliders tend to have more wing to work with than their powered
brothers.

At the risk of starting a religious war, Joe Glider Pilot indeed *can* go
from full flap to zero flap w/o any ill/negatively-dramatic issues in gliders
(BTDT many times, just 'playing around')...with one
theoretical/possibly-real-world exception. The exception, of course, is
getting low and slow on a short final approach with gobs of flap hanging down,
in which case you *are* going to land short, the only question being whether
you do it at a higher speed (i.e. after you've retracted the flaps), or a
slower/lower-energy speed (i.e. playing the hand you've dealt yourself and
hoping for the best while contacting the ground as slowly as
theoretically/practically as is possible for whatever amount of 'too much'
flap you've hanging down). That noted, this exception is meaningful ONLY if
Joe Not-so-clued-in Glider Pilot gets a final approach horribly wrong and
waits until he's completely out of options to do something about it. (Extra
Credit Test Questions: Are you more likely to wind up on a low approach in a
glider with effective drag devices, or one with ineffective ones? Why?

Sure, it's fun - and quite possibly a useful learning exercise - to 'mentally
play with' these sorts of scenarios, but the fact of the matter is Joe Glider
Pilot should *never* 'suddenly' and 'shockingly' find himself hung out to dry
on any normal approach. In fact, I'd argue the only time the possibility of
being 'hung out to dry' should ever even rear its 'might-could-happen' head
are those times when JXCGP has reason to utilize his/the plane's fullest
capabilities shoehorning into a short/obstructed field (which skills of course
shoulda/woulda been safely practiced/determined beforehand)...and even then
the 'need' to do so should've been the result of an active *series* of choices
(maybe not all of them good! ).

Not picking on you...just hypothesizing about possible future realities in any
XC glider pilot's future! As for 'horribly screwing up' a routine approach at
JGP's home field...should never happen, just as a departure from controlled
flight (i.e. the dreaded stall/spin turning base to final) should never
happen. Why would any of us want to go to these places? Yeah, the newer JGP
is, the more likely he is to be making massively large drag device settings
changes in any normal approach (kinda like a new bicycle rider's
easily-detectable large changes to maintain balance, contrasted with an
experienced rider's multitude of 'invisible' corrections), but there's no
'routinely defensible' reason for him to be *aiming* at the absolute near end
of the runway, even when practicing short field approaches.

But it does make sense that you can probably land shorter with these
type of flaps over just spoilers. Now I'll have to go watch the video

Good on you...and may your flying experiences always occur on a happily
expanding palette!


Regards,
Bob W.

On 8/2/2011 8:25 AM, Willy VINKEN wrote:


Lots have been said about flaps-reducing while on final.
I know at least of one other ASH25 pilot who has done it
gently without harmful effects (on final).
Last week, I've tried it in calm evening air at 1500 feet,
checking 2 independent digital altimeters.
A gentle reduction from from 'L' position to neutral made us
loose about 10 feet (natural ~5 second descent included).
A brutal 'L' to 'N' caused a 25-30 feet loss.
Some sailplanes are probably less forgiving.
I'd be glad to hear about pilots who have tried it for real.
wv

I have no ASH 25 experience, but many times (in an HP-14 and a Zuni [think
American design 'PIK-20']) I've gone from full flaps to zero flaps, by way of
learning 'useful bits' about plane/self. All initial experiments, of course,
well distant from the earth...

My HP had hydraulic flaps, which I considered a 'one-shot' in the landing
pattern, due to the 'somewhat funky' valve controlling the hydraulic system
(resetting it in flight was a contortionist's act). Best guess is it lost
perhaps 50 feet when you dumped the flaps, which blew to zero
'instantaneously' at 45 knots indicated. In any event, it distinctly 'settled'
if the stick position was maintained. Simultaneously pulling aft on the stick
when dumping its flaps at 'normal approach speeds' (attempting to maintain the
previous IAS) *seemed* as if it might reduce altitude lost, but that wasn't an
experiment I would've voluntarily tried 'on short final' to verify my surmise!
That said, the HP is the only glider in which I've ever done a 'go-around'.
Youthful stupidity combined with 'contest get-home-itis' brought me and a
nasty T-storm cell overhead the field simultaneously. I wound up dumping full
flaps no more than 300' agl on what I'd intended to be short final but which
transformed to an imminent overshoot due to a positive climb rate with full
flaps (!); the rain obscuring the view directly ahead combined with landing
crosswind on featureless prairie and the sheer (never seen before/since)
unlikely possibility of NOT descending w. full flaps in that ship, combined to
delay my detection of the worsening situation. The hardest part of 'getting
away with it' was resetting the flap valve, which I did on my second downwind
after successfully pulling off the instantaneous-flap-dump/180-degree turn.
(Yes, I re-ran the entire scenario in my mind lots!)

My (flap control mechanisms vary) Zuni's flaps are controlled by a handle
which moves through an arc of ~45-degrees from zero-to-full (~75-degrees), so
flaps can be pulled on/removed as rapidly as one can move arm/handle. It's
essentially pretty simple in the Zuni to dump the flaps while maintaining IAS
within a knot or so as the ship settles. Because the Zuni's flaps are
considerably weaker than were the HP-14's (as in, distinctly less effective
than those of the PIK-20A/Bs I've seen), its 50%/full-flap approach angles are
distinctly shallower than were the HP's. One not-so-great (IMHO) consequence
is, Joe Pilot is more likely to *have to* remove large amounts of flap on
short final in the Zuni if one encounters (say) heavy sink along the way.
BTDT, and removing flaps was never an issue.

In both ships I always simply attempted to fly speed stabilized approaches
regardless of flap position, which - in my experience - is not particularly
difficult. American pilots who've flown (say) Schweizer 1-34s or 2-32s can
easily relate, since with their speed-limiting dive brakes, Joe Pilot has to
effect pitch changes to maintain a constant speed as one modulates their
(very) effective spoilers.

HTH.

Regards,
Bob W.

On Tue, 02 Aug 2011 10:35:37 +0000, Scott
wrote:

On 8-2-2011 02:15, BobW wrote:


IMHO, large deflection landing flaps on gliders are the best kept
sailplane secret in the last half century.

Enjoy!
Bob W.

As a noob to gliders (coming from powered airplanes), I always thought
that spoilers were "the bomb" One thing I like about spoilers over
flaps is that you can go from full spoilers to no spoilers instantly
without bad effects. Can't do that with flaps...if you misjudge and put
on too much, too early, there isn't much you can do except
undershoot...but maybe you can dump some flaps since gliders tend to
have more wing to work with than their powered brothers. But it does
make sense that you can probably land shorter with these type of flaps
over just spoilers. Now I'll have to go watch the video


This is a common misperception among power pilots concerning flaps on
sailplanes.

So long as you keep your approach speeds with a sufficient margin over
your flaps-up stalling speed, you can modulate the flaps as much as
you wish.

....Based in 18 years and 2000+ hrs in a PIK-20B with 90deg flaps.

Currently flying a Ventus C with standard spoilers but still miss the
impressive nose-down approach attitude of a full-flap landing.

Bob

On Aug 2, 2:15*pm, BobW wrote:
As for the rollout, how many 1-26 drivers
routinely roll no more than 300 feet on a hard surface after touchdown? (And
how long does your skid plate last?)

I haven't flown one of those in anger, but most of my genuine landouts
have been in a PW5.

I always pace out the distances afterwards. The usual figures are
about 30 paces from a standard cattle farm fence to the main wheel
touchdown point, and another 30 paces to the point where I'm stopped.

If I call the paces 1m each then that's 200 feet -- from the fence,
not from touchdown.

Most of the rest of my landouts were in a Club Libelle. I'd say the
distances were quite similar. It, of course, has speed limiting
trailing edge airbrakes, which also have enough flap effect to lower
the stall by ~5 knots.


IMHO, large deflection landing flaps on gliders are the best kept sailplane
secret in the last half century.

I'd love to have some! But the trailing edge brakes as on the Club
Libelle, Hornet, Mosquito and I think also the Mini Nimbus and early
Ventus seem to give most of the same benefits, plus some extra ones.

On Aug 2, 10:35*pm, Scott wrote:
As a noob to gliders (coming from powered airplanes), I always thought
that spoilers were "the bomb" * *One thing I like about spoilers over
flaps is that you can go from full spoilers to no spoilers instantly
without bad effects. *Can't do that with flaps...if you misjudge and put
on too much, too early, there isn't much you can do except
undershoot...

You can if you resist the temptation to fly slower than a safe no-flap
speed until you are very close to the ground and/or have the runway
"made". Use the flaps to approach steeper, not to approach slower.

When I was flying a Janus (which has something like a 20º landing flap
position I think), I sometimes practiced going smoothly but reasonably
quickly between no flap and landing flap without feeling a change in G
forces. This involved applying forward elevator at the same time as
increasing the flap setting, and backward elevator at the same time as
reducing the flap setting.

If you do this then you can safely remove flap on approach without any
"sagging", provided that you keep the speed above 50 knots or so. Some
people liked to float the Janus in with landing flap at under 45 knots
on dead calm days, and that's usually going to be ok, but I always
added another 5 knots for my wife and kids. You can get rid of it
quickly enough once you're below a height you don't mind falling from.